1. Field of the Invention
This invention relates to a synchronizing clutch for a manual transmission. More particularly, the invention pertains to a blocking type synchronizing clutch having conical friction components for speed synchronization and clutching teeth for power transmission.
2. Description of the Prior Art
The pin loading synchronizing clutch art includes a class of blocking synchronizers in which a cone clutch is used to synchronize the speed of a gear with the speed of the synchronizer clutch hub through frictional contact and before a positive mechanical connection is made through the engagement of spline teeth. When the clutch sleeve is moved toward a gear, it contacts a tapered surface on the shoulder of pins, which extend through the clutch sleeve and carry at their ends conical friction surfaces that engage internal conical friction surfaces fixed to the gear. The holes through which the pins pass in the sleeve are oversized in relation to the size of the pins and torque developed on the conical friction surfaces drives the pins against one side of the sleeve hole. A chamfer on the pin also causes a torque, which is opposed to the cone torque but of slightly lower magnitude. Therefore, the sleeve will not move axially toward the gear until this block is removed. When speed synchronization is completed and the cone torque drops to zero, the torque caused by the sleeve riding on the pin chamfers moves the pins aside and lock-up is completed on a set of splines. Examples of synchronizers of this type are described in U.S. Pat. Nos. 3,286,801 and 4,138,007.
One disadvantage of conventional pin type synchronizer clutches, especially when they are used in small manual transmissions, is that the external cone element attached to the gear appreciably increases the rotating inertia of the gear about its polar axis and therefore increases the work required of the vehicle operator to produce a gear change. It is preferable that the positions of the internal and external cone elements be reversed from the positions they occupy in conventional prior art synchronizing clutches by placing the internal cone element on the gear and the external element on the synchronizer. This change reduces the reflected inertia of the components that must be synchronized during a gear change in a manual transmission. U.S. Pat. No. 4,138,007 shows the conventional location of the internal element fixed to the gears. U.S. Pat. Nos. 2,395,189, 2,451,513 and 2,479,184 describe the location of the external cone element fixed to the gears and the internal cone element fixed to the synchronizer.